Use Animation Playback when frames have different names
The operator doesn't expose any options you could set, but this seems to be the command it uses:

'C:\\Program Files\\Blender Foundation\\Blender\\blender.exe -a -f 24 1.0 -s 1 -e 250 -j 1 C:\\tmp\\0001.png'


There's even a step / frame jump parameter:

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Command_Line#Animation_Playback_Options:

But it doesn't really help in your case. You need to specify every single frame:

blender -a -f 24 1.0 00_0001.png 25_0002.png 50_0003.png 75_0004.png